I need to be able to sync in real time my email, calendar, tasks and contacts. Basically everything from my Outlook Exchange 2007 server needs to sync with the BB.

You can't do what you want to do.
Without BES, you can't wirelessly sync your Contacts, Calendar, Tasks, Memos.

You may be able to use BIS to get your corporate email, but your company would need to provide public OWA or IMAP access to your mailbox.
Even so... OWA 2007 is not officially supported on BIS yet. Some have gotten it to work.

You should be able to sync your PIM data via USB cable and Desktop Manager, if your company permits its use on their computers in your office.